There is a lot of good content on the internet that explains how to secure a Spring API with Keycloak: Create a Client that represents the API Service in Keycloak and use a link like the one below to get the access and refresh token:
<Domain>/auth/realms/<realm>/protocol/openid-connect/auth/{some parameters}
This yields both tokens. So far so good.
Now, however, I am not sure how the flow for the frontend accessing the API should look like.
Should the frontend directly access this endpoint and, therefore, obtain the access and refresh token? That would mean that the API can only have the access-type public because there is no way to store the client (the API) secret securely.
Or should there be a third server that somehow stores the refresh token for each user, that the user can call if his access token is no longer valid. This server would then use the client's refresh token (and the client secret that could be stored securely, since it would be in the backend) to get a new access token from Keycloak and would forward it to the user.
I guess the main question that I am asking is, whether the client/user should get the refresh token.
If one needs to implement a logic according to the second option, I would be interested in a link or description of how something like this can be done in Spring.
